Melanoma (malignant melanoma) is a superficial tumor occurring on the surface of a human body. It looks like a mole. However, if it is assumed as an ordinary mole and is touched or surgically operated, it metastasizes to the whole body and leads to death. It is known that the melanoma metastasizes even by irradiating it with ultraviolet rays of blue wavelength or shorter. Namely, only diagnosing it has a risk of metastasis. Even now, it is said that such a diagnosis relies on experienced doctors and their instinct. It is strongly desired, therefore, to provide a measuring apparatus capable of objectively diagnosing a skin problem such as melanoma without experienced doctors.